Illustration Brain Synapses

UC Riverside mouse study reveals where in the brain sensory input is changed to movement.

When we step on the vehicle brake upon seeing a red traffic light ahead, a series of occasions unfolds in the brain at lightning speed.

The image of the traffic light is moved from our eyes to the visual cortex, which, in turn, communicates to the premotor cortex– an area of the brain associated with preparing and executing limb motions. A signal is then sent to our foot to step on the brake. However, the brain area that helps the body go from “seeing” to “stepping” is still a secret, aggravating neuroscientists and psychologists.

To unload this “black box,” a group of neuroscientists at the University of California, Riverside, has experimented on mice to identify the brain area that functions beyond sensory encoding and motor encoding, potentially opening up new directions to studying the cellular and circuit systems of sensory-motor transformations. The researchers report a cortical region generally defined as hair motor cortex in mice is most straight associated to the transformation process.

In the lab, the researchers skilled mice to sense a slight deflection on one side of their hairs, and report if they noticed it by licking a water port.

” We recorded the neuronal activity of some brain regions that may communicate this sensory-motor improvement by utilizing the ‘language of neurons’– the electrical signals– produced as the mouse performs the job of stimulus detection,” stated Zhaoran Zhang, a graduate student in the Neuroscience Graduate Program and a co-first author of the research paper released in eNeuro, an open-access journal of the Society of Neuroscience.

Behzad Zareian, a graduate student in the Department of Psychology and a co-first author of the research paper, explained the team used easy however instinctive mathematical tools to transform the neurons’ electrical activities to numbers that explain how much the neurons pick up the sensory input, just how much they reflect the upcoming movement outputs, and how well they predict whether the sensory information can be successfully changed to a correct habits.

Behzad Zareian, Edward Zagha, and Zhaoran Zhang

Zoom picture shows, from L to R, Behzad Zareian, Edward Zagha, and Zhaoran Zhang. Credit: Zagha lab, UC Riverside

” We found a brain area generally specified as the hair motor cortex, which was previously believed to influence how a mouse moves its hairs,” Zareian stated, “We found this cortical area can transforming the sensory input from whisker deflection to a more general motion action– licking in this case– instead of simply moving whiskers.”

Corresponding author Edward Zagha, an assistant professor of psychology and the team’s principle private investigator, discussed that a person problem in discovering brain areas running the sensory-motor transformation is that although scientists can determine the sensory- and motor-related brain activities easily in the lab, the inner procedure that conducts the sensory-motor transformation in the brain is evasive and hard to quantify.

” Our brain represents sensory and motor information in more than one place and typically in a redundant way for several functions such as fine-tuning future movements, enhancing perception or memory storage,” Zagha stated. “Hence, researchers are now able to differentiate the place of transformation and the areas that merely reflect the sensory or motor information for other functions. This can significantly enhance the use of targeted treatment for patients with sensory- and motor-related brain deficits.”

Next, the team plans to focus its research study on whisker motor cortex to show what takes place within this area to allow the improvement procedure.

” Remarkably, each cortical area includes multiple layers and multiple subtype of neurons such as excitatory and repressive nerve cells that are subject to research study,” Zagha stated. “Hence, this broadens our knowledge of the neurobiological circuits carrying out sensory-motor improvements and recognizes sites of prospective restorative intervention to modulate these brain functions.”

Referral: “Cortical Localization of the Sensory-Motor Improvement in a Hair Detection Task in Mice” by Behzad Zareian, Zhaoran Zhang and Edward Zagha, 25 January 2021, eNeuro
DOI: 10.1523/ ENEURO.0004-212021

The research was moneyed by grants from the Whitehall Structure and National Institutes of Health.

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